Along with development of the large area geographic information system (GIS) data collection devices, studies about building modeling (in particular, roof modeling and reconstruction) have shown a rising trend in the past several years. Realistic roof modeling has become increasingly popular in urban planning, navigation, and GIS. Two types of roof modeling include (1) mesh modeling and (2) roof style modeling. The mesh model preserves detailed low-level geometry, but may not be practical to render such models on certain devices. Additionally, no semantic information may be directly available using the mesh model.
On the other hand, roof style modeling enables realistic roof modeling at a semantic level and may be rendered more efficiently. Roof style modeling and reconstruction may use various data sources such as aerial imagery, ground level imagery, and light detection and ranging (LiDAR). Roof geometry structures and topologies may be analyzed, which may require complete and specific source data of the roof. In some examples, only a limited number of roof styles may be recognized and classified.
Aerial imagery, as one of the most popular data source of the large area geo-information, has drawn many scholars' attentions. Drawbacks of using aerial image come in several folds. At first, building image quality is highly depends on circumstances, detection of building and corresponding features can easily fail due to unexpected degradation such as occlusion or blur. Furthermore, building modeling through image only is more fragile due to lack of height information of building. Therefore, building and roof modeling is a continuing effort.